SCIENTIFIC SUMMARY. 
233 
A New Meteorite. — It is stated that some very large and heavy meteorites, 
which fell during last summer in Hungary, have been recently examined. 
The circumstances under which the fall occurred are interesting, the sky 
being quite clear, between four and five in the afternoon. At the time of the 
fall, a violent detonation was heard, similar to that produced by the simul- 
taneous discharge of a hundred cannons. The meteorites appeared as a 
greyish cloud, about the size of the sun’s disc, uniting on all sides columns 
of greyish smoke, but without a trace of luminous appearance. Two or three 
minutes after this appearance, a noise was heard like that of a multitude of 
stones rattling together ; this lasted for ten or fifteen minutes, and, after it, the 
fall of stones took place. Several eye-witnesses, at localities six to twelve 
Austrian miles distant, describe the meteor as having presented the appearance 
of a yellow and orange luminous globe, followed by a train bordered with 
ultramarine blue. About sixty stones were collected, and were found to pos- 
sess the usual characters of meteors, being covered also with a layer of black 
enamel. The heaviest of these weighed 550 lbs. ; it was broken in two by 
the violence of the shock, and from the violence with which it fell to the 
earth, it passed into the soil to the depth of about eleven Austrian feet, in 
this way forming a hole or pit nearly four feet wide. At a temperature of 
20° Reaumur, they had a specific gravity of 3-520. When first found, the 
meteorites were quite hot, and some of them retained their heat for several 
days. 
The Detection of “ Tears ” in Lenses. — The presence, in lenses, of spots of a 
different refracting power from the rest of the lenses, is a serious difficulty in 
optical experimentation. It is, therefore, interesting to know that Herr A. 
Topler has discovered a very useful method of detecting these portions 
[tears] in lenses. The mode which this physicist adopts is as follows : — The 
light proceeding from a bright lamp, through the aperture of a small shade, 
falls upon a system of lenses, which should be as achromatic and aplanatic as 
possible. The transmitted light concentrates in a focus, at a distance of from 
ten to twenty-five feet on the other side. A simple Keplerian telescope of 
two lenses is so set up that its optical axis coincides with that of the system 
of lenses above mentioned, and that the focus of the rays issuing from the 
system of lenses lies in front of the object-glass of the telescope. The tele- 
scope, moreover, is so drawn out that the rays issuing from the eye-piece 
have their point of junction at the pupil of the eye, and hence project on 
the retina the image of an uniformly illuminated field of view. If a screen 
be laterally pushed in front of the object-glass of the telescope, as soon as 
its edge passes by the place of the focus the field of view will at once be- 
come dark ; if, either in the glass of the system of lenses in question, or in 
media which are placed before or behind it, there are places of different 
densities ; some rays will, therefore, be deflected from their path — they will 
not pass through the focus, and hence will not disappear when the screen is 
pushed across. These rays then give an image of the u tears ” in the dark 
field of view. 
The Optical Analysis of Sound. — Herr A. Topler has pointed out an im- 
proved method of analysing vibrations by an optical method. We cannot 
here give any adequate explanation of the principle on which his apparatus 
is employed. We, therefore, commend the reader to the author’s paper on 
